Generate DSA SHA1PRNG signature - Java Security

Java examples for Security:DSA

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Description

Generate DSA SHA1PRNG signature

Demo Code


import java.io.*;
import java.security.*;

class GenSig {/*from  w  w w.  jav a2 s .  com*/

    public static void main(String[] args) {

        if (args.length != 1) {
            System.out.println("Usage: GenSig nameOfFileToSign");
        } else
            try {

                KeyPairGenerator keyGen = KeyPairGenerator.getInstance(
                        "DSA", "SUN");
                SecureRandom random = SecureRandom.getInstance("SHA1PRNG",
                        "SUN");
                keyGen.initialize(1024, random);

                KeyPair pair = keyGen.generateKeyPair();
                PrivateKey priv = pair.getPrivate();
                PublicKey pub = pair.getPublic();

                Signature dsa = Signature.getInstance("SHA1withDSA", "SUN");
                dsa.initSign(priv);

                FileInputStream fis = new FileInputStream("helloji");
                BufferedInputStream bufin = new BufferedInputStream(fis);
                byte[] buffer = new byte[1024];
                int len;
                while ((len = bufin.read(buffer)) >= 0) {
                    dsa.update(buffer, 0, len);
                }
                ;
                bufin.close();

                byte[] realSig = dsa.sign();

                FileOutputStream sigfos = new FileOutputStream(
                        "E:/Dan.txt");
                sigfos.write(realSig);
                sigfos.close();

                byte[] key = pub.getEncoded();
                FileOutputStream keyfos = new FileOutputStream(
                        "E:/Danpub.txt");
                keyfos.write(key);
                keyfos.close();

            } catch (Exception e) {
                System.err.println("Caught exception " + e.toString());
            }
    }
}

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